Investigation of the International Passamaquoddy Tidal Power Project
Total Page：16
File Type：pdf, Size：1020Kb
INVESTIGATION OF THE INTERNATIONAL PASSAMAQUODDY TIDAL POWER PROJECT BROCHURE I REPORT TO THE INTERNATiONAL JOINT COMMISSION BY THE INTERNATIONAL PASSAMAQUODDY ENGINEERING BOARD October 1959 INVESTIGATION OF THE INTERNATIONAL PASSAMAQUODDY TIDAL POWER PROJECT -.. a:~ High tide Eastport,,, . Maine - - -, ' I .-- REPORT TO THE ENTERNATIONAL JOINT COMMISSION BY THE INTERNATIONAL PASSAMAQUODDY ENGINEERING BOARD October 1959 BROCHURE In accordance with United States Public Law 401,84th Congress, 2nd Session, and the Boundary Waters Treaty of 1909, the Governments of Canada and the United States in August 1956 directed the International Joint Commission to investigate the engineering and economic feasibility of harnessing the tides of Passamaquoddy and Cobscook Bays in the Province of New Brunswick and the State of Maine for production of hydroelectric power. The investigation, completed in October 1959 well within the appropriations authorized by both countries, established the type and cost of the most economical project to generate electricity from the tides, and determined whether tidal power could be generated at a price competitive with the most economical alternative source of power. To carry out the investigation of the tidal power project and its effect on the economies of the United States and Canada, including the fisheries of the area, the Commission established two separate boards, the International Passamaquoddy Engineering Board and the International Passa- maquoddy Fisheries Board. Composed of two representatives each from Canada and the United States, the boards were directed to coordinate their studies and to submit separate reports to the Commission. The Engineering Board in turn established an Engineering Committee to supervise the detailed investigations. These investigations were carried out primarily by the U.S. Army Engineer Division, New England, Corps of Engineers, and the Regional Office of the United States Federal Power Commission, New York. Canadian aspects of the survey were conducted by the Department of Public Works, the Department of Northern Affairs and National Resources, and other agencies of the Federal and Provincial Governments of Canada . This syllabus presents a brief summary of the report of the International Passamaquoddy Engineering Board, including the Board's conclusions on engineering and economic feasibility. HARNESSING THE TIDES Man has for centuries devised methods of Tidal hydroelectric power, similar to putting the ocean tides to work. As early as river hydro power, can be produced by a flow the eleventh century tides were harnessed in of water from a higher to a lower level a small way in England and other Western through hydraulic turbines. A single pool European countries when small tide mills equipped with gates may be built to trap were used to grind corn. In Chelsea, water at high tide and discharge through Massachusetts, in 1734 "Slade's Mill" was turbines to the ocean at low tide, or the pool built to grind spices. This mill developed may be emptied at low tide to receive turbine about 50 horsepower from four water wheels discharge from the ocean at high tide. Two driven by the head created by damming a separate pools equipped with emptying and small estuary to trap water at high tide. filling gates may be used, one pool filled at Since the advent of hydroelectric power, high tide and the other emptied at low tide, numerous tidal power sites throughout the with the high pool discharging through the , world have been investigated. In addition to turbines into the low pool. the Pas samaquoddy Bay area, a few of the locations recently studied for large tidal A single high pool has the serious dis- power plants include the tidal estuary of the advantage of producing discontinuous power, River Severn in England, the Bay of LIAber because no power can be generated without a Vrach on the northwest coast of Brittany, sufficient difference between the level of the Mont St. Michel in northwest France near pool and the level of the ocean. Thus no St. Malo, and the Gulf of San Jose' in generation is possible until the ocean has Argentina. Components of what may be the receded sufficiently to obtain this difference world's fir st large- scale tidal power plant in water levels, or power head; nor is are now being tested to harness the La Rance generation possible on the rising tide after River estuary on the Brittany coast. the level of the ocean becomes too high to provide this minimum necessary head. For simplified illustration, the sun and, moon similar reasons, a single low pool also appear on the same side of the earth approxi- produces interrupted power. This dis- mately every four weeks, at the time of new advantage is avoided in the two-pool plan, moon. Two weeks later, at the time of full the plan adopted for the project described in moon, the sun and moon appear on opposite this report, which generates varying but sides of the earth. When either of these continuous amounts of power. This con- conditions occurs, gravitational attraction of tinuous power is achieved in the two-pool the sun and moon reinforce each other and plan by operating emptying and filling gates cause maximum or spring tides. When the so that the level of one pool is always moon is at either quarter phase, the gravi- sufficiently higher than the other. tational attraction of the sun and moon are approximately at right angles with respect to The advantages of a tidal power plant are the earth, causing minimum or neap tides. that the tides, which can be predicted with When the moon is new or full and simul- accuracy for many years in the future, can taneously in perigee -- the point in the moon's produce power unaffected by droughts, floods, orbit closest to earth - - the spring tide is ice jams, or silting -- adverse factors which particularly great. decrease the output and limit the life of river hydroelectric plants. An inherent disad- The height the tide will reach is also vantage of the tides as a source of power is affected, sometimes to a high degree, by the that the tides, following the gravitational coastline. On open, exposed headlands tides pull of the moon as it passes overhead every may range from 4 to 5 feet, while in nearly 24 hours and 50 minutes, are out of phase landlocked embayments, like the Mediter- with the 24-hour solar day. This 50 minute ranean, tides are negligible. In the Gulf of daily lag is fundamental to the economics of Maine, however, which opens toward the deep tidal power for, since power output varies areas of the Atlantic Ocean as the continental with the tides, tidal power is completely out shelf drops off beyond Georges and Browns of step with the normal patterns of daily use banks, the tides are greatly amplified by the of electricity. Therefore, unless the tidal size and configuration of the shore and plant is supplemented by an auxiliary power bottom. As shown on plate 1, the mean tidal plant, such varying power would be of little ranges become progressively greater as the value. tides move into the Gulf of Maine toward the mouth of the Bay of Fundy. The funnel- Tidal ranges, the height between high and shaped Bay of Fundy again amplifies the tidal low tides, determines the available head and range, producing the highest tides in the thus governs the amount of power generated. world at the head of the bay. To devise a 1 Tides are caused by the changing relation- workable and feasible scheme to harness ship of the sun, earth and moon with respect these tides for the economical production of to each other, and tidal range, which is uninterrupted power constitutes the essence affected primarily by the phases of the moon, of tidal power engineering. also varies from day to day. As shown in the PHASES OF THE MOON 7* Midnisht * ' Noon Mldnipht EL_. 8- -- - ' I TIDAL CYCLE liCOSTi SLAND 1 OF PSAZNT LAWRENCE '- 1 BRETON PRJNCE EDWARD , lSCkND "' L Sable GULF AUGUST 1959 4- " --'-" Generation of hydroelectric power from The major differences between the 1935-37 the tides within the Bay of Fundy has intrigued project and the project which is the subject of engineers in Canada and the United States for this report are that (1) the project proposed over forty years. At Burntcoat Head in the in this report is an international two-pool Minas Basin at the head of the Bay of Fundy project which permits production of continuous in Canada, the spring tides reach an extreme power; and (2) that a river hydroelectric range of over 50 feet. The range of the tides auxiliary plant is used to firm the tidal plant in Passamaquoddy and Cobscook Bays near output. Compared to the single-pool project the mouth of the Bay of Fundy, the site of the planned in 1935-37, these differences are tidal project described in this report, varies highly advantageous. from a minimum of 11.3 feet at neap tide to a maximum of 25.7 feet at spring tide, As the result of continued interest in the averaging 18.1 feet. During each tidal cycle, Passamaquoddy tidal power project on the an average volume of approximately 70 billion part of the people of Maine and New cubic feet of water regularly enters and Brunswick, supported by an increasing leaves Passamaquoddy and Cobscook Bays. awareness of the need to exploit all possible sources of energy, the International Joint As early as 1919, W. R. Turnbull of Commission was requested in 1948 by both Saint John, New Brunswick, suggested pro- governments to review all previous r-eports duction of hydroelectric power from the great and to estimate the cost of carrying out a tides at the head of the Bay of Fundy in the complete study in order to decide conclusively Petitcodiac and Memramcook estuaries .